Human breast milk contains 200 or more kinds of human milk oligosaccharides (HMOs) having a unique structure at a considerably higher concentration (5 to 15 g/L) than other mammal's breast milk.
Breastfeeding during infancy is considerably important since HMOs provide various biological activities that have positive influences on infant development and health, such as prebiotic effects, prevention of pathogen infection, regulation of the immune system, and brain development.
Breast milk contains about 200 kinds of oligosaccharides. Among them, 2′-fucosyllactose and 3′-fucosyllactose are reported to be main HMOs that are involved in various biological activities. For this reason, in recent years, fucosyllactose draws a great deal of attention because it has potential to be used for powdered milks for infants, health functional food materials for elderly people and medicinal materials. However, it is known that about 20% of women cannot synthesize fucosyllactose well due to mutation of fucose transferase that synthesizes fucosyloligosaccharide. For this reason, there is a need for industrial production of fucosyllactose.
However, since industrial mass-production of fucosyllactose is difficult at present, instead of fucosyllactose, galactooligosaccharide or fructooligosaccharide, which is an analogue of fucosyllactose, is added to baby food, to offer similar effects thereto.
Meanwhile, methods of producing fucosyllactose include direct extrusion from breast milk, and chemical or enzymatic synthesis.
Direct extraction has drawbacks of limited breast milk supply and low productivity. Chemical synthesis has drawbacks of expensive substrates, low stereo-selectivity and production yield, and use of toxic organic solvents. In addition, enzymatic synthesis has drawbacks in that GDP-L-fucose used as a donor of fucose is very expensive and purification of fucosyltransferase involves high costs.
Due to the aforementioned drawbacks, it is difficult to apply direct extraction, and chemical or enzymatic production to mass-production of fucosyllactose and there are almost no technologies for mass-production. However, since it is possible to expect development of functional health foods and medicinal materials using 2′-fucosyllactose, a great deal of research is needed for industrial production of 2′-fucosyllactose using microorganisms.
In addition, the majority of conventional methods for producing 2′-fucosyllactose using microorganisms were production using recombinant Escherichia coli. However, most Escherichia coli used for experimentation are predominantly known to be harmful to customers although they are not pathogens.
In addition, since an ingredient for the cell membrane of Escherichia coli may serve as endotoxin, high isolation and purification costs are involved in the production of 2′-fucosyllactose. Accordingly, there is a difficulty in using Escherichia coli as a host cell that produces fucosyllactose which is one of food and medicinal materials.